Some underbody support mattresses for use during medical procedures use inflatable chambers as the support mechanism. The patient must be allowed to “sink” into the inflatable chambers if they are going to provide maximal surface contact with the patient's body in order to minimize the contact pressure at any given point, thus preventing pressure injury to the patient's skin. “Maximally” sinking into the inflatable chamber could be achieved by releasing air from the chamber until the moment before the most protruding body part of the patient touches the base layer of the mattress or the hard surface below the mattress. At this moment, the patient is maximally engulfed and supported by the mattress, much like floating in water. The problem is that there is currently no reliable way of determining when the most protruding patient part is near bottoming out versus actually touching the bottom.
Currently available underbody support mattresses with inflatable chambers adjust to a desired air pressure that is determined by the operator. Whether or not the patient sinks into the mattress and whether or not the body part that is most protruding “bottoms out” by touching the base layer of the mattress is totally a function of the operator guessing at the correct pressure setting. Some mattresses with inflatable chambers claim to analyze derivatives of the change in pressure to determine the optimal support pressure. However, none of these pressure-based control systems reliably allow the patient to sink maximally into the mattress until the most protruding body part is an optimal 0.5-1.0 inches from bottoming out. In this condition, all body parts are supported by air and yet the mattress maximally accommodates the patient's body for maximal contact pressure relief—similar to floating in water. There is a need for a better and more reliable control mechanism for reliably determining the maximum safe accommodation before any body part “bottoms out.” Additionally, there is a need for a safety sensor that can detect changes in body positioning and/or loss of air from the inflatable chambers resulting in inadvertent “bottoming out,” that may convert a safe condition into a dangerous condition over time, for example due to an air leak.
In addition, there are challenges to accurately measuring core body temperature through the skin and peripheral thermal compartment. There is a need for accurately and non-invasively measuring core body temperature during medical procedures such as surgery.
Grounding electrodes have been used during surgery for many decades. The electrical pathway for the radio-frequency (RF) electro-surgical units can be completed by directly applying a grounding pad to the patient's skin for direct electrical conduction. Alternately, grounding can be accomplished by placing a larger electrode under the patient which is not in direct electrical contact but rather creates a condition of capacitive coupling for grounding the RF electrical current, as described; for example, in U.S. Pat. Nos. 6,053,910 and 6,214,000. However, these capacitive coupling electrodes have been generally utilized as mattress overlays which are inconvenient, require extra cleaning and are usually embedded into a heavy, cumbersome gel pad.
Keeping the patient from sliding off of the surgical table when the table is tilted into a steep, head-down (Trendelenburg) position, is a constant challenge for surgical personnel and a danger for the patient. This problem has gotten worse in recent years with the advent of laparoscopic surgery and particularly with the advent of robotic surgery. In both of these instances, the patients are regularly placed into steep Trendelenburg so that gravity can move the internal organs out of the way of the laparoscopes. A reliable and convenient way of stabilizing the patient on the surgical table is needed for the Trendelenburg and other unusual positions.